Pleural lesions composed of spindle fibroblast-like cells embedded in collagenous stroma comprise both neoplastic and reactive diseases. The differential diagnosis includes such common entities as chronic fibrous pleuritis and pleural plaques, less frequent ones such as solitary fibrous tumour, and such rare ones as desmoplastic malignant mesothelioma, calcifying tumour and desmoid tumour. The diagnosis, not easy in a postoperative specimen, is particularly difficult in small biopsy material. Clinical and radiological correlation as well as immunohistochemical reactions are needed and are often essential to establish the final diagnosis.

Detailed differentiation of rare spindle cell pleural lesions in microscopic analysis, immunohistochemistry, clinical course and radiological examination is described in this article.